Wheeler
Reservoir

Ecological
health rating

The ecological health of Wheeler Reservoir rated poor in 2011. Wheeler Reservoir rated either good or fair in all previous years except 2007, when it also rated poor. Generally, lower ecological health scores occur during years with lower flow. Low-flow-years typically result in higher chlorophyll concentrations and worse dissolved oxygen conditions.

TVA monitors four locations on Wheeler Reservoir—the deep, still water near the dam, called the forebay; the middle part of the reservoir; the Elk River embayment; and the riverlike area at the extreme upper end of a reservoir, called the inflow—usually on a two-year cycle.

Wheeler
Reservoir Ecological Health Ratings, 1994-2011

Click chart for raw
data.

The table below shows the ratings for individual ecological health indicators at Wheeler in 2011. These ratings are briefly explained in the paragraphs that follow.

Ecological
Health Indicators at
Wheeler Reservoir, 2011

Monitoring
locations

Dissolved
oxygen

Chlorophyll

Fish

Bottom
life

Sediment

Dissolved oxygen

Dissolved oxygen rated good at the mid-reservoir location and poor at both the forebay and Elk River embayment due to low concentrations (less than two milligrams per liter of oxygen) in the lower water column during the summer. Dissolved oxygen has rated good at the mid-reservoir location in all previous years, but ratings have varied between good, fair and poor at the forebay and embayment locations, primarily in response to reservoir flows.

Chlorophyll

Chlorophyll rated poor at all locations because concentrations were elevated in most of the samples collected. Chlorophyll typically rates poor at the forebay and Elk River embayment, but ratings have varied between good, fair and poor at the mid-reservoir location.

Fish

The fish community rated good at the forebay and inflow and fair at the mid-reservoir and Elk River embayment locations. Ratings have fluctuated between good and fair at each location. Fair ratings were largely due to the collection of fewer fish and fish species than expected, and often a greater proportion of those were tolerant individuals (e.g. bluegill and largemouth bass). 2005 was the only year the fish community rated good at all locations.

Bottom life

Bottom life rated poor at the forebay and Elk River embayment, fair at the mid-reservoir, and good at the inflow monitoring location. The lower ratings were due to relatively sparse populations, predominantly composed of animals able to tolerate poor water quality (i.e., low dissolved oxygen).

Sediment

Sediment quality rated good at the mid-reservoir because no PCBs or pesticides were detected, and concentrations of metals were within expected background levels. Sediment quality rated fair at the forebay and Elk River embayment locations due to the presence of PCBs. Sediment quality typically rates good in Wheeler Reservoir. Exceptions were fair ratings at the mid-reservoir in 1994, 1995, and 2003 when low levels of pesticides (DDT/DDD or chlordane) were detected.

See definitions of
ecological health indicators and monitoring locations.

Fish
consumption advisories

Wheeler Reservoir - TVA maintains a program to examine contaminants in fish fillets from TVA reservoirs and their major tributary streams on a rotational basis. The data collected from this program is distributed to the state officials who are responsible for placing or removing fish tissue consumption advisories on those bodies of water. For information on advisories currently in effect for Wheeler Reservoir, visit the Epidemiology Division of Alabama Department of Public Health’s web page.http://www.adph.org/tox/index.asp?ID=1360

Wheeler Reservoir is located on
the Tennessee River in north central Alabama.